[Retention of organic solvent vapors in plastic bags. Part 5. A basic study about correction methods of concentration of organic solvent vapors in plastic bags (author's transl)].

The concentration of organic solvents in plastic bags is decreased with time elapsed. It was supposed to permeate in plastic films. Therefore, we assumed that this phenomenon will be approximately regulated by the first order order reaction (C = C0e-kt). We got the permeation coefficient (k) by experiments and used it to correct organic solvent concentrations in the plastic bags. In the present experiment, we used Tedlar bags, toluene and ethyl methyl ketone (MEK) as organic solvents and determined the values by gas chromatography. Initial organic solvents concentration and that after t hr standing being taken as C0 and C. k Values are obtained by the formula C = C0e-kt. Mean values of k about toluene and MEK were found: k = 6.00 X 10(-3) and k = 4.86 X 10(-3). The results by this correction were as follows: Retention of toluene concentration in 24 hr standing bags showed to increase from 81% to 93%, or, in the case of 96 hr standing bags, it was shown to increase from 56% to 100%. Retention of MEK concentration in 24 hr standing bags showed to increase from 86% to 97%, or, in the case of 96 hr standing bags, it was shown to increase from 68% to 109%.